OFFSET
0,3
LINKS
E. Bannai, S. T. Dougherty, M. Harada and M. Oura, Type II Codes, Even Unimodular Lattices and Invariant Rings, IEEE Trans. Information Theory, Volume 45, Number 4, 1999, 1194-1205.
Index entries for linear recurrences with constant coefficients, signature (2, -1, 4, -8, 4, -6, 12, -6, 4, -8, 4, -1, 2, -1).
FORMULA
G.f.: (5*x^12 + 51*x^11 + 190*x^10 + 400*x^9 + 846*x^8 + 947*x^7 + 882*x^6 + 795*x^5 + 304*x^4 + 152*x^3 + 36*x^2 - x + 1)/((x - 1)^6*(x^2 + x + 1)^4).
a(n) ~ 64*n^5/135. - Stefano Spezia, Aug 21 2022
MATHEMATICA
CoefficientList[Series[(5x^12+51x^11+190x^10+400x^9+846x^8+947x^7+882x^6+795x^5+304x^4+152x^3+36x^2-x+1)/((x-1)^6(x^2+x+1)^4), {x, 0, 40}], x] (* or *) LinearRecurrence[ {2, -1, 4, -8, 4, -6, 12, -6, 4, -8, 4, -1, 2, -1}, {1, 1, 37, 229, 721, 2152, 5083, 10167, 19637, 34575, 56511, 90552, 138093, 201909}, 40] (* Harvey P. Dale, Jul 14 2021 *)
CROSSREFS
KEYWORD
nonn,easy,nice
AUTHOR
EXTENSIONS
More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jun 15 2001
STATUS
approved